npm install poolifier --save

You can implement a worker in a simple way , extending the class ThreadWorker :

'use strict'
const { ThreadWorker } = require('poolifier')

function yourFunction (data) {
  // this will be executed in the worker thread,
  // the data will be received by using the execute method
  return { ok: 1 }
}

module.exports = new ThreadWorker(yourFunction, { maxInactiveTime: 60000, async: false })

Instantiate your pool based on your needed :

'use strict'
const { FixedThreadPool, DynamicThreadPool } = require('poolifier')

// a fixed thread pool
const pool = new FixedThreadPool(15,
  './yourWorker.js',
  { errorHandler: (e) => console.error(e), onlineHandler: () => console.log('worker is online') })

// or a dynamic thread pool
const pool = new DynamicThreadPool(10, 100,
  './yourWorker.js',
  { errorHandler: (e) => console.error(e), onlineHandler: () => console.log('worker is online') })

pool.emitter.on('FullPool', () => console.log('Pool is full'))

// the execute method signature is the same for both implementations,
// so you can easy switch from one to another
pool.execute({}).then(res => {
  console.log(res)
}).catch .... 

See examples folder for more details ( in particular if you want to use a pool for multiple functions ).

You can use node versions 12.x , 13.x, 14.x

numThreads (mandatory) Num of threads for this worker pool
filePath (mandatory) Path to a file with a worker implementation
opts (optional) An object with these properties :

• errorHandler - A function that will listen for error event on each worker thread
• onlineHandler - A function that will listen for online event on each worker thread
• exitHandler - A function that will listen for exit event on each worker thread
• maxTasks - This is just to avoid not useful warnings message, is used to set maxListeners on event emitters ( workers are event emitters)

min (mandatory) Same as FixedThreadPool numThreads , this number of threads will be always active
max (mandatory) Max number of workers that this pool can contain, the new created threads will die after a threshold ( default is 1 minute , you can override it in your worker implementation).
filePath (mandatory) Same as FixedThreadPool
opts (optional) Same as FixedThreadPool

Execute method is available on both pool implementations ( return type : Promise):
data (mandatory) An object that you want to pass to your worker implementation

Destroy method is available on both pool implementations.
This method will call the terminate method on each worker.

fn (mandatory) The function that you want to execute on the worker thread
opts (optional) An object with these properties :

• maxInactiveTime - Max time to wait tasks to work on ( in ms) , after this period the new worker threads will die.
• async - true/false , true if your function contains async pieces else false

See guidelines CONTRIBUTING
Choose your task here 2.0.0, propose an idea, a fix, an improvement.

MIT